Transformer Oil Spectroscopy vs. Oil Chromatography: A Comprehensive Comparison of Two DGA Online Monitoring Technologies
Date: June 13, 2026, 02:12:02
- chromatography: Gas chromatography is the most mature and well-established technical approach in the field of online DGA monitoring. After physical separation in the chromatographic column, the gas mixture is analyzed component by component, allowing for the simultaneous detection of seven or more fault-indicating gases and providing strong diagnostic capabilities. This method requires the use of carrier gas and periodic replacement of the chromatographic column.
- spectroscopy: Photoacoustic spectroscopy directly identifies gases using their characteristic absorption spectra, eliminating the need for chromatographic columns and carrier gas systems. It features a simpler design, requires less maintenance, and offers faster detection speeds; however, the range of detectable gases and the completeness of its standards are not as extensive as those of chromatography.
- The two are not mutually exclusive.: Each of these two technologies has its own optimal application scenarios. Chromatography is suitable for the comprehensive monitoring needs of hub substations, while spectroscopy is suitable for distributed sites with limited maintenance capabilities.
1. Comparison of Technical Principles
| dimension (math.) | gas chromatography | photoacoustic spectroscopy |
|---|---|---|
| Detecting gas type | 7 or more | 3 to 7 types |
| Consumables requirements | Carrier Gas + Chromatography Column | Virtually no consumables |
| Maintenance requirements | moderate | lower (one's head) |
| Technology maturity | Improvements to IEC/GB Standards | Standard Under Development |
| Scenario | 220 kV+ Main Transformer, Critical Equipment | Unattended stations, distributed sites |
2. Recommendations for Selecting Solutions Based on Specific Scenarios
2.1 Main Transformer at the Hub Substation— Chromatography-based methods take priority. Comprehensive gas coverage and authoritative diagnostics based on IEC/GB standards are the primary considerations. Decades of experience with chromatography have provided the most extensive set of criteria and data support.
2.2 Remote Unmanned Stations— Priority Spectroscopy Method. Its maintenance-free nature is a decisive advantage. For sites that are difficult to access and where maintenance personnel cannot visit frequently, reducing even a single maintenance trip can result in significant savings in operations and maintenance costs.
2.3 High-Low Combination Scheme— Chromatography is used at central stations and spectroscopy at distributed sites within the same power grid, with unified management via a single monitoring platform. This approach balances diagnostic depth with operational and maintenance cost-effectiveness.
3. Frequently Asked Questions FAQ
3.1 Q: Can the data from the two technologies be directly compared?
Answer: Absolute gas readings obtained from devices using different detection principles may vary. For a single transformer, the same monitoring technology should be used consistently to ensure the consistency of trend data.
3.2 Q: Will spectroscopic methods eventually replace chromatographic methods?
Answer: It will not completely replace it in the short term. The two technologies are more complementary than competitive. Chromatography’s position in the field of comprehensive diagnostics will remain unshaken in the short term, while spectroscopy offers unique advantages in maintenance-free applications.
Disclaimer: The content of this article is for technical exchanges and reference only, and does not constitute any form of procurement commitment or contract offer. Product technical parameters, configuration programs and prices are subject to the actual signed contracts and technical agreements.
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